Class: ShopifyCli::ProcessSupervision

Inherits:
Object
  • Object
show all
Defined in:
lib/shopify-cli/process_supervision.rb

Overview

ProcessSupervision wraps a running process spawned by exec and keeps track if its pid and keeps a log file for it as well

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(identifier, pid: nil, time: Time.now.strftime('%s')) ⇒ ProcessSupervision

:nodoc:



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# File 'lib/shopify-cli/process_supervision.rb', line 131

def initialize(identifier, pid: nil, time: Time.now.strftime('%s')) # :nodoc:
  @identifier = identifier
  @pid = pid
  @time = time
  FileUtils.mkdir_p(ShopifyCli::ProcessSupervision.run_dir)
  @pid_path = File.join(ShopifyCli::ProcessSupervision.run_dir, "#{identifier}.pid")
  @log_path = File.join(ShopifyCli::ProcessSupervision.run_dir, "#{identifier}.log")
end

Instance Attribute Details

#identifier ⇒ Object (readonly)

a string or a symbol to identify this process by



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# File 'lib/shopify-cli/process_supervision.rb', line 9

def identifier
  @identifier
end

#log_path ⇒ Object (readonly)

filepath to the logfile for this process



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# File 'lib/shopify-cli/process_supervision.rb', line 17

def log_path
  @log_path
end

#pid ⇒ Object

process ID for the running process



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# File 'lib/shopify-cli/process_supervision.rb', line 11

def pid
  @pid
end

#pid_path ⇒ Object (readonly)

filepath to the pidfile for this process



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# File 'lib/shopify-cli/process_supervision.rb', line 15

def pid_path
  @pid_path
end

#time ⇒ Object (readonly)

starttime of the process



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# File 'lib/shopify-cli/process_supervision.rb', line 13

def time
  @time
end

Class Method Details

.for_ident(identifier) ⇒ Object

Will find and create a new instance of ProcessSupervision for a running process if it is currently running. It will return nil if the process is not running.

#### Parameters

  • identifier - a string or a symbol that a process was started with

#### Returns

  • process - ProcessSupervision instance if the process is running this will be nil if the process is not running.



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# File 'lib/shopify-cli/process_supervision.rb', line 38

def for_ident(identifier)
  pid, time = File.read(File.join(ShopifyCli::ProcessSupervision.run_dir, "#{identifier}.pid")).split(':')
  new(identifier, pid: Integer(pid), time: time)
rescue Errno::ENOENT
  nil
end

.run_dir ⇒ Object 



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# File 'lib/shopify-cli/process_supervision.rb', line 20

def run_dir
  # is the directory where the pid and logfile are kept
  File.join(ShopifyCli.cache_dir, 'sv')
end

.running?(identifier) ⇒ Boolean

will help identify if your process is still running in the background.

#### Parameters

  • identifier - a string or symbol to identify the new process by.

#### Returns

  • running - [true, false]

Returns:

  • (Boolean) 


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# File 'lib/shopify-cli/process_supervision.rb', line 124

def running?(identifier)
  process = for_ident(identifier)
  return false unless process
  process.alive?
end

.start(identifier, args) ⇒ Object

will fork and spawn a new process that is separate from the current process. This process will keep running beyond the command running so be careful!

#### Parameters

  • identifier - a string or symbol to identify the new process by.

  • args - a command to run, either a string or array of strings

#### Returns

  • process - ProcessSupervision instance if the process is running, this will be nil if the process did not start.



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# File 'lib/shopify-cli/process_supervision.rb', line 59

def start(identifier, args)
  return for_ident(identifier) if running?(identifier)

  # Windows doesn't support forking process without extra gems, so we resort to spawning a new child process -
  # that means that it dies along with the original process if it is interrupted. On UNIX, we fork the process so
  # that it doesn't have to be restarted on every run.
  if Context.new.windows?
    pid_file = new(identifier)

    # Make sure the file exists and is empty, otherwise Windows fails
    File.open(pid_file.log_path, 'w') {}
    pid = Process.spawn(
      *args,
      out: pid_file.log_path,
      err: pid_file.log_path,
      in: Context.new.windows? ? "nul" : "/dev/null",
    )
    pid_file.pid = pid
    pid_file.write

    Process.detach(pid)
  else
    fork do
      pid_file = new(identifier, pid: Process.pid)
      pid_file.write
      STDOUT.reopen(pid_file.log_path, "w")
      STDERR.reopen(pid_file.log_path, "w")
      STDIN.reopen("/dev/null", "r")
      Process.setsid
      exec(*args)
    end
  end

  sleep(0.1)
  for_ident(identifier)
end

.stop(identifier) ⇒ Object

will attempt to shutdown a running process

#### Parameters

  • identifier - a string or symbol to identify the new process by.

#### Returns

  • stopped - [true, false]



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# File 'lib/shopify-cli/process_supervision.rb', line 107

def stop(identifier)
  process = for_ident(identifier)
  return false unless process
  process.stop
end

Instance Method Details

#alive? ⇒ Boolean

will help identify if your process is still running in the background.

#### Returns

  • alive - [true, false]

Returns:

  • (Boolean) 


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# File 'lib/shopify-cli/process_supervision.rb', line 166

def alive?
  stat(pid)
end

#stop ⇒ Object

will attempt to shutdown a running process

#### Parameters

  • ctx - the context of this command

#### Returns

  • stopped - [true, false]



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# File 'lib/shopify-cli/process_supervision.rb', line 151

def stop
  kill_proc
  unlink
  true
rescue
  false
end

#write ⇒ Object

persists the pidfile



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# File 'lib/shopify-cli/process_supervision.rb', line 173

def write
  FileUtils.mkdir_p(File.dirname(pid_path))
  File.write(pid_path, "#{pid}:#{time}")
end